In drilling wells for oil and gas exploration, understanding the structure and properties of the associated geological formation provides information to aid such exploration. Measurements may be performed in a borehole to obtain this information. However, the environment in which the drilling tools operate and where measurements are made may be located at significant distances below the surface. It may be desirable to transmit downhole measurements to the surface for analysis and control purposes.
Electrical cables have been investigated for high speed communications to and from downhole tools. Use of electrical cables for such communication, however, has drawbacks due to limitations with information bandwidth. Optical fibers have also been investigated for high speed communications to and from downhole tools to overcome the information bandwidth limitations of electrical cables. However, optical fiber cables typically need near perfect optical alignment at their connections in order to achieve low signal loss.